Influence of Rhizosphere Fungi on Essential Oil Production and Menthol Content in Mentha arvensis L.

In recent days Good Agricultural Practices are followed for the production of quality raw material. Additionally there are increasing interest on the role of rhizosphere fungi for the enhancing the quality of active compounds of medicinal and aromatic plants. Mentha arvensis L. is an important medicinal and aromatic plant cultivated for its essential oil (EO) used for treating diseases and disorders by traditional healers. In the present investigation rhizosphere soil samples of M arvensis were collected from Mahatma Phule Krishi Vidyapeeth (MPKV), Rahuri. The most abundant rhizosphere fungal species were found namely, Aspergillus niger (42.02 %), Rhizopus stolonifer (23.1 8%), R. nigricans (15.95 %) followed by A. flavus (2.89 %), R. nodosus (2.89 %), A. terreus (1.44 %), A. Parasiticose (1.44 %), A. terricola (1.44 %), A. sclerotioniger (1.44 %), Nigrospora sphaerica (1.44 %), Trichoderma viride (1.44 %), T harzianum (1.44 %), A. fumigatus (1.44 %) and Zygorhynchus molleri (1.44 %). Influence of rhizosphere fungi on EO of Al. arvensis seedlings was studied by using pots containing inoculated soil. Essential oil content showed a maximum of 0.88 % in the treatment of T viride followed by A. niger (0.78 %), A. flavus (0.72 %), T harzianum, R. nodosus (0.56 %), A. terreus (0.53 %) and R. stolonifer (0.45 %). A minimum of 0.42 % content was observed in the treatments ofA. terricola inoculants. T viride inoculated plants also had significant highest concentration of menthol (98.25 %) in comparison to other rhizosphere fungi. T harzianum with (98.7 %) menthol followed by R. stolonifer, A. niger (98.06 %), R. nodosus (97.78 %), A. flavus (97.72 %), A. terricola (96.42 %), Z. moelleri (93.71 %) and A. terreus (91.47 %).